Intercooler apparatus

ABSTRACT

An intercooler apparatus (C) for a supercharged internal combustion engine comprises a heat exchanger (19) through which charged air for combustion passes prior to entry into a combustion chamber (17) of the engine. A refrigeration unit (20) provides the heat exchanger (19) with coolant comprising air cooled to a temperature below ambient temperature which removes heat from the charged air.

DESCRIPTION OF INVENTION

This invention relates to an intercooler apparatus for a superchargedinternal combustion engine.

It will be appreciated that in charging air for use in an internalcombustion engine, the air becomes compressed and therefore is heated.

Intercoolers are known which cool charged air prior to the charged airentering the combustion chamber of the engine, thus to improve theefficiency of the engine.

Arrangements are known for example from U.S. Pat. No. 4,736,727 in whichthe charged air for an internal combustion engine of a vehicle is cooledby the action of air at ambient temperature passing a heat exchangerthereof, either as the vehicle moves, or due to the action of a fan.With such an arrangement, the charged air cannot be cooled below theambient air temperature.

Arrangements are also known, for example from Japanese patentapplication JP 61037523 in which refrigerant is circulated both to anair conditioning unit and to an air intercooler to cool charged air.This requires an unduly long refrigerant circuit and complicated controlmechanisms.

According to one aspect of the invention we provide an intercoolerapparatus for a supercharged internal combustion engine comprising aheat exchanger through which charged air for combustion passes prior toentry into a combustion chamber of the engine, and means to provide tothe heat exchanger, coolant comprising air cooled to a temperature belowambient temperature which removes heat from the charged air.

The cooled air may be cooled by a refrigeration unit which may be drivenfrom the engine.

For economic reasons, the refrigeration unit preferably is not dedicatedsolely to the intercooler apparatus, but rather preferably therefrigeration unit is operable otherwise to provide cooling.

For example the internal combustion engine may be controlled from anoperator'cab and the refrigeration unit may be operable in addition toproviding coolant air to the heat exchanger of the intercoolerapparatus, to provide cooled air for the operator's cab.

The cooled air for the intercooler apparatus may be bled from a cooledair feed between the refrigeration unit and the operator's cab or viceversa.

Preferably though the refrigeration unit has a first cooled air outletconnected to the operator's cab and a second cooled air outlet which isconnected to the heat exchanger of the intercooler apparatus.

In each case, preferably a control means is provided which is capable ofproviding for a proportion of, or even all of the air cooled by therefrigeration unit to be fed to the intercooler apparatus.

According to a second aspect of the invention we provide a systemcomprising an internal combustion engine, a supercharger for chargingcombustion air for the internal combustion engine, and an intercoolerapparatus, the intercooler apparatus comprising a heat exchanger throughwhich charged air for combustion passes prior to entry into thecombustion chamber of the engine, a refrigeration unit for providing tothe heat exchanger of the intercooler apparatus coolant comprising aircooled to a temperature below ambient temperature, thereby to removeheat from the charged air.

The system may comprise part of a machine such as an excavator and/orloader or crane wherein the engine is operable to provide power fordigging and/or loading and/or lifting operations. Alternatively oradditionally, the system may comprise part of a vehicle such as atractor having wheels or tracks or other ground-engaging drive meansdriven from the engine.

In each case, the refrigeration unit may be operative to provide furthercooling for example to cool air for an operator's cab of themachine/vehicle from which the internal combustion engine is controlled.

The invention will now be described with reference to the accompanyingdrawings in which:

FIG. 1 is a side illustrative view of a digging/excavating machine inaccordance with the invention,

FIG. 2 is an illustrative view of a first embodiment of an intercoolerapparatus in accordance with the invention,

Referring to FIG. 1, an excavating/loading machine comprises a body 10mounted on wheels 11, the body 10 housing an engine 12 which providespower to a drive transmission to drive the wheels 11, and to a hydraulicpump for operation of a loading arm 13 and/or an excavating arm 14mounted on the body 10. Thus the machine can perform loading, diggingand lifting operations and be driven over the ground.

The engine 12 (and loading arm 13 and excavating arm 14) are controlledfrom within an operator's cab 15 which is air conditioned for thecomfort of the operator.

The engine 12 is of the supercharged type in which the combustion air,rather than being naturally induced into the engine by the action ofpistons in cylinders thereof, is driven into the engine by asupercharging means. The supercharging means may be driven from theexhaust of the engine, or otherwise as desired.

To improve the efficiency of the engine, it is desirable that thecharged air is as cool as possible when it enters the combustion chamberof the engine 12.

Referring to FIG. 2, a first embodiment of the invention is illustrated.Air for combustion is charged by a supercharging means 16 and is fedinto a combustion chamber 17 of the engine 12 via an air feed 18. Thecombustion air is warmed by the action of the supercharging means 16 andso, before being fed into the combustion chamber 17, the air passesthrough a heat exchanger 19 of an intercooler apparatus C, andconsequently the charged air gives off heat to the coolant in the heatexchanger 19. The coolant comprises air cooled by a refrigeration unit20 which is also operable to condition air for the operator's cab 15.

Air at ambient temperature is drawn by a fan F through an inlet I of therefrigeration unit 20 into an evaporator unit 21 and is cooled byrefrigerant R passing through the evaporator unit 21. The evaporatorunit 21 has a first cooled air outlet 22 which extends to and isconnected to the cab 15 whereby cooled air can be directed into the cab15, and a second cooled air outlet 23 which extends to and is connectedto the heat exchanger 19 of the intercooler apparatus C. Air cooled bythe refrigeration unit 20 is thus warmed in the heat exchanger 19 byheat absorbed from the charged combustion air, and is then vented toatmosphere via outlet 24 from the heat exchanger 19.

It will be appreciated that refrigerant for the evaporator unit 21 iscompressed and condensed by the refrigeration unit 20 by a conventionalcompression and/or absorption refrigeration process. For example, therefrigeration unit may include a compressor pump 30 and a condenser 31.

Hence air drawn into the evaporator unit 21 through inlet I at ambienttemperature will be cooled to below ambient temperature such that thecooled air for the heat exchanger 19 of the intercooler apparatus C isalso below ambient temperature. The charged air from the superchargingmeans 16 will in general have a temperature above ambient temperature bywhich we mean the temperature at which the combustion air is fed to thecharging means 16 through inlet 25.

In a modified arrangement instead of the evaporator unit 21 having firstand second separate outlets 22,23 for the cooled air for the cab 15and/or the heat exchanger 19 of the intercooler apparatus C, a portionof the cooled air can be bled from the cooled air as it is fed to thecab 15 from outlet 22, to the intercooler apparatus C, or vice versa.

In each case, it is preferred that the prime function of therefrigeration unit 20, is to provide cooled air to the intercoolerapparatus C, the cab 15 or other cooling being a secondary function.This is to ensure that engine performance is maintained. Thus in theevent that there is any competition for cooled air, the refrigerationunit 20 may be arranged to provide up to its entire capacity of cooledair for use in the intercooler apparatus C, and a restricted supply ofcooled air or no cooled air at all, for use in cooling the cab 15.

In the arrangement shown in FIG. 2, this may be achieved by providing inat least outlet 22 from the evaporator 21, a butterfly or other kind ofvalve V which can be closed to varying degrees to permit a greaterproportion, or even all of the air cooled in the refrigeration unit 20to be available for the intercooler apparatus C.

In an alternative arrangement in which the evaporator 21 has a singleoutlet with a branch to enable the bleeding of cooled air to theintercooler apparatus C or the cab 15, a similar butterfly valvearrangement may be provided between the bleed connection and the cab 15.

In each case, it is envisaged that in normal operation of the engine 12,cooled air would be shared between the intercooler apparatus C and thecab 15, but in the event that enhanced engine performance is required,for example so that a difficult digging or excavating operation can moreeasily be performed, the operator can operate a control of a controlmeans so that the butterfly valve V would be closed, and all of thecooled air provided by the refrigeration unit 20 would become availableto the intercooler apparatus C.

Of course, during such an operation, cooled air would not be availablefor the cab 15.

In a modified arrangement, if desired, the outlet 23 from therefrigeration unit 20 may additionally have a butterfly or other valveif required, under the control of a control means, such as for exampleonly, an electronic engine management system M so as to enable finecontrol over the amount of cooled air fed to the intercooler apparatusC.

The control means M may otherwise be operable for controlling therefrigeration unit 10.

Preferably though, the intercooler apparatus C need not comprise anyseparate control means to control the degree of cooling of the chargedair, but the degree of cooling of the charged air is controlled solelyas a result of the usual controls provided for the refrigeration unit 20from which cooled air is obtained.

Various modifications may be made to the invention. For example,although in the embodiments described, cooled air for the heat exchanger19 for the intercooler apparatus C is obtained from a refrigeration unit20 which is also operable to condition air for the cab 15, cooled airmay be obtained from a refrigeration unit 20 which is operable otherwiseto provide cooling. For example, where the invention is applied to avehicle rather than an excavating and/or loading machine 10 asdescribed, the refrigeration unit 20 from which cooled air is obtainedfor the intercooler apparatus C, may be operable to providerefrigeration in a goods storage space.

If desired, in addition to a refrigeration unit 20, to provide cooledair to the intercooler apparatus C, means may be provided to supply airat ambient temperature to the intercooler apparatus C, or additionalintercooler means, at least partially to cool the supercharged airtowards the temperature of the ambient air. The air at ambienttemperature may be arranged to be fed to the intercooler apparatus C orto the additional intercooler means when cooled air is not beingsupplied thereto from the refrigeration unit 20, or at the same time,the air at ambient temperature partially cooling the supercharged airbefore this is cooled by the cooled air from the refrigeration unit 20.

The features disclosed in the foregoing description the following claimsor the accompanying drawings, expressed in their specific forms or interms of a means for performing the disclosed function, or a method orprocess for attaining the disclosed result, or a class or group ofsubstances or compositions, as appropriate, may, separately or in anycombination of such features, be utilised for realising the invention indiverse forms thereof.

We claim:
 1. An intercooler apparatus for a supercharged internalcombustion engine having a combustion chamber, comprises a heatexchanger, means to pass charged air for combustion through the heatexchanger, prior to entry into the combustion chamber of the engine, andmeans to provide to the heat exchanger coolant wherein the coolantcomprises air cooled to a temperature below ambient temperature whichcooled air removes heat from the charged air.
 2. An apparatus accordingto claim 1 wherein the cooled air is cooled by a refrigeration unit. 3.An apparatus according to claim 2 wherein the refrigeration unit isdriven from the engine.
 4. An apparatus according to claim 2 wherein therefrigeration unit is operable otherwise to provide cooling.
 5. Anapparatus according to claim 4 wherein the internal combustion engine iscontrolled from an operator's cab and the refrigation unit is operableto provide cooled air for the operator's cab.
 6. An apparatus accordingto claim 5 wherein the cooled air for the intercooler apparatus is bledfrom an air feed between the refrigeration unit and the operator's cabor vice versa.
 7. An apparatus according to claim 5 wherein therefrigeration unit has a first cooled air outlet connected to theoperator's cab and a second cooled air outlet which is connected to theheat exchanger of the intercooler apparatus.
 8. An apparatus accordingto claim 5 wherein a control means is provided which is capable ofproviding for at least a proportion of the air cooled by therefrigeration unit to be fed to the intercooler appparatus.
 9. A systemcomprising an internal combustion engine having a combustion chamber, asupercharger for charging combustion air for the internal combustionengine, and an intercooler apparatus, the intercooler apparatuscomprising a heat exchanger and means to pass charged air for combustionthrough the heat exchanger prior to entry into the combustion chamber ofthe engine wherein there is provided a refrigeration unit for providingto the heat exchanger of the intercooler apparatus air at a temperaturebelow ambient temperature, thereby to remove heat from the charged air.10. A system according to claim 9 which comprises part of an excavatingand/or loading machine wherein the engine is operable to provide powerfor digging and/or loading and/or lifting operations.
 11. A systemaccording to claim 10 which comprises part of a vehicle and a machine,having ground-engaging drive means driven from the engine.
 12. Anapparatus according to claim 5 wherein the cooled air for the operator'scab is bled from an air feed between the refrigeration unit and theintercooler apparatus.